Field of the Invention
The present disclosure relates to an organic light emitting display.
Discussion of the Related Art
Recently, various flat panel displays that are less bulky and lighter than cathode ray tubes (CRTs) are being developed. Examples of the flat panel displays include liquid crystal displays (LCDs), field emission displays (FEDs), plasma display panels (PDPs), organic light-emitting displays (OLEDs), etc. Among these types of flat panel displays, the organic light-emitting displays are self-luminous displays that emit light through excitation of organic compounds. The organic light emitting diode displays work without a backlight used in LCDs; thus, they can be lighter and thinner and made in a simplified process. Also, the organic light emitting diode displays can be manufactured at low temperatures, have a fast response time of 1 ms or less, and feature low power consumption, wide viewing angle, and high contrast.
An organic light-emitting display comprises an emissive layer of organic materials between a first electrode as an anode and a second electrode as a cathode. As such, a hole from the first electrode and an electron from the second electrode recombine within the emissive layer, forming an exciton, i.e., a hole-electron pair. Then, energy is created as the exciton returns to the ground state, thereby causing the organic light-emitting display to emit light. Organic light-emitting displays may be classified as bottom-emission devices and top-emission devices depending on the direction light exits the device. In the case of the bottom-emission devices, light exits towards the bottom of the substrate, that is, from the emissive layer to the first electrode. In the case of the top-emission devices, light exits towards the top of the substrate, that is, from the emissive layer to the second electrode.
With increasingly higher resolution displays becoming available, they need smaller pixel sizes. Thus, the design limit requirements for a layout that requires circuit configuration within a limited space are getting tighter. In this case, there may be problems (structural weak spots), including the failure to form capacitors and their disappearance due to a short-circuit between electrodes, which need to be solved.